CA3017996A1 - Iron based powder - Google Patents
Iron based powder Download PDFInfo
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- CA3017996A1 CA3017996A1 CA3017996A CA3017996A CA3017996A1 CA 3017996 A1 CA3017996 A1 CA 3017996A1 CA 3017996 A CA3017996 A CA 3017996A CA 3017996 A CA3017996 A CA 3017996A CA 3017996 A1 CA3017996 A1 CA 3017996A1
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 157
- 239000000843 powder Substances 0.000 title claims abstract description 137
- 229910052742 iron Inorganic materials 0.000 title claims description 55
- 239000010949 copper Substances 0.000 claims abstract description 90
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 82
- 229910052802 copper Inorganic materials 0.000 claims abstract description 81
- 239000002245 particle Substances 0.000 claims abstract description 39
- 238000009792 diffusion process Methods 0.000 claims abstract description 36
- 239000000203 mixture Substances 0.000 claims description 40
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 31
- 238000000034 method Methods 0.000 claims description 30
- 239000011148 porous material Substances 0.000 claims description 26
- 238000004519 manufacturing process Methods 0.000 claims description 25
- 229910002804 graphite Inorganic materials 0.000 claims description 18
- 239000010439 graphite Substances 0.000 claims description 18
- 230000008569 process Effects 0.000 claims description 18
- 238000005056 compaction Methods 0.000 claims description 17
- 229910052799 carbon Inorganic materials 0.000 claims description 14
- 239000000314 lubricant Substances 0.000 claims description 14
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 13
- 229910052760 oxygen Inorganic materials 0.000 claims description 13
- 239000001301 oxygen Substances 0.000 claims description 13
- 239000000654 additive Substances 0.000 claims description 8
- 238000005245 sintering Methods 0.000 claims description 8
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 claims description 7
- 238000002149 energy-dispersive X-ray emission spectroscopy Methods 0.000 claims description 7
- 238000002156 mixing Methods 0.000 claims description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 6
- 238000000137 annealing Methods 0.000 claims description 5
- 230000002708 enhancing effect Effects 0.000 claims description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 4
- 229910052739 hydrogen Inorganic materials 0.000 claims description 4
- 239000001257 hydrogen Substances 0.000 claims description 4
- 230000003287 optical effect Effects 0.000 claims description 4
- 239000012535 impurity Substances 0.000 claims description 3
- 229910052757 nitrogen Inorganic materials 0.000 claims description 3
- 238000010791 quenching Methods 0.000 claims description 3
- 230000000171 quenching effect Effects 0.000 claims description 3
- 230000009467 reduction Effects 0.000 claims description 3
- 239000007789 gas Substances 0.000 claims description 2
- 230000006698 induction Effects 0.000 claims description 2
- 230000007935 neutral effect Effects 0.000 claims description 2
- 239000005751 Copper oxide Substances 0.000 claims 1
- 229910000431 copper oxide Inorganic materials 0.000 claims 1
- 238000005275 alloying Methods 0.000 description 9
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 238000005204 segregation Methods 0.000 description 5
- BERDEBHAJNAUOM-UHFFFAOYSA-N copper(I) oxide Inorganic materials [Cu]O[Cu] BERDEBHAJNAUOM-UHFFFAOYSA-N 0.000 description 4
- KRFJLUBVMFXRPN-UHFFFAOYSA-N cuprous oxide Chemical group [O-2].[Cu+].[Cu+] KRFJLUBVMFXRPN-UHFFFAOYSA-N 0.000 description 4
- 238000010410 dusting Methods 0.000 description 4
- 239000000047 product Substances 0.000 description 4
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000012512 characterization method Methods 0.000 description 2
- 229940112669 cuprous oxide Drugs 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 239000012467 final product Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000005749 Copper compound Substances 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 229910021383 artificial graphite Inorganic materials 0.000 description 1
- 238000000889 atomisation Methods 0.000 description 1
- 239000010953 base metal Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 150000001880 copper compounds Chemical class 0.000 description 1
- IYRDVAUFQZOLSB-UHFFFAOYSA-N copper iron Chemical compound [Fe].[Cu] IYRDVAUFQZOLSB-UHFFFAOYSA-N 0.000 description 1
- 229960004643 cupric oxide Drugs 0.000 description 1
- 238000002050 diffraction method Methods 0.000 description 1
- ALKZAGKDWUSJED-UHFFFAOYSA-N dinuclear copper ion Chemical compound [Cu].[Cu] ALKZAGKDWUSJED-UHFFFAOYSA-N 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 238000009661 fatigue test Methods 0.000 description 1
- 238000000445 field-emission scanning electron microscopy Methods 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 230000004083 survival effect Effects 0.000 description 1
- 238000009692 water atomization Methods 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
- B22F1/05—Metallic powder characterised by the size or surface area of the particles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
- B22F1/05—Metallic powder characterised by the size or surface area of the particles
- B22F1/052—Metallic powder characterised by the size or surface area of the particles characterised by a mixture of particles of different sizes or by the particle size distribution
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
- B22F1/06—Metallic powder characterised by the shape of the particles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
- B22F1/10—Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
- B22F1/17—Metallic particles coated with metal
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/12—Both compacting and sintering
- B22F3/16—Both compacting and sintering in successive or repeated steps
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/24—After-treatment of workpieces or articles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/02—Making ferrous alloys by powder metallurgy
- C22C33/0235—Starting from compounds, e.g. oxides
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/02—Making ferrous alloys by powder metallurgy
- C22C33/0257—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements
- C22C33/0264—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements the maximum content of each alloying element not exceeding 5%
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/24—After-treatment of workpieces or articles
- B22F2003/248—Thermal after-treatment
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F2301/00—Metallic composition of the powder or its coating
- B22F2301/35—Iron
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F2302/00—Metal Compound, non-Metallic compound or non-metal composition of the powder or its coating
- B22F2302/25—Oxide
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
- B22F2998/10—Processes characterised by the sequence of their steps
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12014—All metal or with adjacent metals having metal particles
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
- Y10T428/12611—Oxide-containing component
Abstract
Disclosed is a new diffusion-bonded powder consisting of an iron powder having 1-5%, preferably 1.5-4% and most preferably 1.5-3.5% by weight of copper particles diffusion bonded to the surfaces of the iron powder particles. The new diffusion bonded powder is suitable for producing components having high sintered density and minimum variation in copper content.
Description
IRON BASED POWDER
FIELD OF THE INVENTION
The present invention relates to an iron based powder intended for the powder metallurgical manufacturing of components. The invention further relates to a method of manufacturing the iron based powder and a method for manufacturing a component from said iron based powder and an accordingly produced component.
BACKGROUND
In industry the use of metal products manufactured by compacting and sintering iron-based powder compositions is becoming increasingly widespread. The quality requirements of these metal products are continuously raised, and as a consequence, new powder compositions having improved properties are developed. Beside density, one of the most important properties of the final, sintered products is the dimensional change, which above all have to be con-sistent. Problems with size variations in the final product often originates from inhomogenities in the powder mixture to be compacted. Such inhomogenities may also lead to variations in mechanical properties of the final components.
These problems are especially pronounced with powder mixtures including pulverulent components, which differ in size, density and shape, a reason why segregation occurs during handling of the powder composition. This segregation implies that the powder composition will be non-uniformly composed, which in turn means that parts made of the powder composition exhibits varying dimensional change during its production and the final product will have varying properties. A further problem is that fine particles, particularly those of lower density such as graphite, cause dusting in the handling of the powder mixture.
Differences in particle size also create problems with the flow properties of the powder, i.e. the capacity of the powder to behave as a free-flowing powder. An impaired flow manifests itself in increased time for filling dies with powder, which means lower productivity and an increased risk of variations in density and composition of the compacted component, which may lead to unacceptable deformations after sintering.
Attempts have been made at solving the problems described above by adding various binding agents and lubricants to the powder composition. The purpose of the binder is to bind firmly and effectively the small size particles of additives, such as alloying components, to the surface of the base metal particles and, consequently, reduce the problems of segregation and dusting. The purpose of the lubricant is to reduce the internal and external friction during compaction of the powder composition and also reduce the ejection force, i.e. the force required to eject the finally compacted product from the die.
The most commonly employed powder compositions for manufacturing of components by compaction and sintering contains iron, copper and carbon, as graphite, in powder form. In addition, a powdered lubricant is also normally added. The content of copper is normally between 1-5% by weight of the composition, the content of graphite between 0.3-1.2% by weight and the content of lubricant is normally below 1 /0 by weight.
The alloying element carbon, as graphite, is normally present as discrete particles in the powder which particles may be bonded to the surface of the coarser, low carbon containing, iron- or iron based powder in order to avoid segregation and dusting. The option of adding carbon as a pre-alloyed element in the iron or iron based powder, i.e. added in the melt before atomization, is not an alternative as such high carbon containing iron or iron- based powder would be too hard and extremely difficult to compact.
The alloying element copper may be added in elemental form as a powder and optionally bonded to the iron or iron based powder by means of a binder. A more efficient alternative to avoid e.g. copper segregation and copper dusting is however to diffusion bond, partially alloy, copper particles to the surface of the iron or iron based powders. By this method an unacceptable increase of the hardness of the iron or iron-based powder is avoided which otherwise would be a consequence if copper was allowed to be totally alloyed, pre-alloyed, to the iron or iron- based powder.
Diffusion bonded powders where copper is diffusion bonded to the surface of the iron or iron- based powder have been known for decades. In the GB patent GB1162702, 1965, (Stosuy) a process for preparing a powder is disclosed. In this process alloying elements are diffusion-bonded, partially
FIELD OF THE INVENTION
The present invention relates to an iron based powder intended for the powder metallurgical manufacturing of components. The invention further relates to a method of manufacturing the iron based powder and a method for manufacturing a component from said iron based powder and an accordingly produced component.
BACKGROUND
In industry the use of metal products manufactured by compacting and sintering iron-based powder compositions is becoming increasingly widespread. The quality requirements of these metal products are continuously raised, and as a consequence, new powder compositions having improved properties are developed. Beside density, one of the most important properties of the final, sintered products is the dimensional change, which above all have to be con-sistent. Problems with size variations in the final product often originates from inhomogenities in the powder mixture to be compacted. Such inhomogenities may also lead to variations in mechanical properties of the final components.
These problems are especially pronounced with powder mixtures including pulverulent components, which differ in size, density and shape, a reason why segregation occurs during handling of the powder composition. This segregation implies that the powder composition will be non-uniformly composed, which in turn means that parts made of the powder composition exhibits varying dimensional change during its production and the final product will have varying properties. A further problem is that fine particles, particularly those of lower density such as graphite, cause dusting in the handling of the powder mixture.
Differences in particle size also create problems with the flow properties of the powder, i.e. the capacity of the powder to behave as a free-flowing powder. An impaired flow manifests itself in increased time for filling dies with powder, which means lower productivity and an increased risk of variations in density and composition of the compacted component, which may lead to unacceptable deformations after sintering.
Attempts have been made at solving the problems described above by adding various binding agents and lubricants to the powder composition. The purpose of the binder is to bind firmly and effectively the small size particles of additives, such as alloying components, to the surface of the base metal particles and, consequently, reduce the problems of segregation and dusting. The purpose of the lubricant is to reduce the internal and external friction during compaction of the powder composition and also reduce the ejection force, i.e. the force required to eject the finally compacted product from the die.
The most commonly employed powder compositions for manufacturing of components by compaction and sintering contains iron, copper and carbon, as graphite, in powder form. In addition, a powdered lubricant is also normally added. The content of copper is normally between 1-5% by weight of the composition, the content of graphite between 0.3-1.2% by weight and the content of lubricant is normally below 1 /0 by weight.
The alloying element carbon, as graphite, is normally present as discrete particles in the powder which particles may be bonded to the surface of the coarser, low carbon containing, iron- or iron based powder in order to avoid segregation and dusting. The option of adding carbon as a pre-alloyed element in the iron or iron based powder, i.e. added in the melt before atomization, is not an alternative as such high carbon containing iron or iron- based powder would be too hard and extremely difficult to compact.
The alloying element copper may be added in elemental form as a powder and optionally bonded to the iron or iron based powder by means of a binder. A more efficient alternative to avoid e.g. copper segregation and copper dusting is however to diffusion bond, partially alloy, copper particles to the surface of the iron or iron based powders. By this method an unacceptable increase of the hardness of the iron or iron-based powder is avoided which otherwise would be a consequence if copper was allowed to be totally alloyed, pre-alloyed, to the iron or iron- based powder.
Diffusion bonded powders where copper is diffusion bonded to the surface of the iron or iron- based powder have been known for decades. In the GB patent GB1162702, 1965, (Stosuy) a process for preparing a powder is disclosed. In this process alloying elements are diffusion-bonded, partially
- 2 -alloyed, to the iron powder particles. An unalloyed iron powder is heated together with alloying elements, such as copper and molybdenum, in a reducing atmosphere at a temperature below the melting point to cause partially alloying and agglomeration of the particles. The heating is discontinued before complete alloying and the obtained agglomerate is ground to a desired size. Also the GB
patent GB1595346, 1976, (Gustaysson), discloses a diffusion-bonded powder.
The powder is prepared from a mixture of an iron powder and a powder of copper or easily reducible copper compounds. The patent application discloses an iron-copper powder having a content of 10% by weight of diffusion bonded copper. This master powder is diluted with plain iron powder and the resulting copper content in the powder composition is 2% respective 3% by weight of the powder composition.
Examples of other patent documents disclosing various copper containing diffusion bonded iron or iron ¨ based powders are JP3918236B2 (Kawasaki), JP63-114903A (Toyota), JP8-092604 (Dowa), JP1-290702 (Sumitomo).
The Kawasaki patent document describes a manufacturing method for manufacturing a diffusion bonded powder where atomized iron powder having an oxygen content of 0.3-0.9% and a carbon content less than 0.3% is mixed with a coarse metal copper powder having an average particle size of 20-100 m.
The Toyota patent application discloses a highly compressible metal powder consisting of a pre-alloyed iron powder having particles of copper diffusion bonded to its surfaces. The pre-alloyed iron powder is composed of 0.2-1.4% Mo, 0.05-0.25% Mn and less than 0.1% C, all percentage by weight of the pre-alloyed iron powder. The pre-alloyed iron powder is mixed with copper powder or copper oxide powder having a weight average particle size of at most 1/5 of the weight average particle size of pre-alloyed iron powder, the mixture is heated whereby the copper particles are diffusion bonded to the pre-alloyed iron powder. The copper content of the resulting diffusion bonded powder is 0.5-5%
by weight.
In the Dowa patent application, it is described a manufacturing method for producing a diffusion bonded copper containing iron powder wherein fin particulate copper oxide powder having a particle size of at most 51.1.m and a specific surface area of at least 10m2/g, is mixed with an iron containing powder. The mixture between the copper oxide powder and the iron containing
patent GB1595346, 1976, (Gustaysson), discloses a diffusion-bonded powder.
The powder is prepared from a mixture of an iron powder and a powder of copper or easily reducible copper compounds. The patent application discloses an iron-copper powder having a content of 10% by weight of diffusion bonded copper. This master powder is diluted with plain iron powder and the resulting copper content in the powder composition is 2% respective 3% by weight of the powder composition.
Examples of other patent documents disclosing various copper containing diffusion bonded iron or iron ¨ based powders are JP3918236B2 (Kawasaki), JP63-114903A (Toyota), JP8-092604 (Dowa), JP1-290702 (Sumitomo).
The Kawasaki patent document describes a manufacturing method for manufacturing a diffusion bonded powder where atomized iron powder having an oxygen content of 0.3-0.9% and a carbon content less than 0.3% is mixed with a coarse metal copper powder having an average particle size of 20-100 m.
The Toyota patent application discloses a highly compressible metal powder consisting of a pre-alloyed iron powder having particles of copper diffusion bonded to its surfaces. The pre-alloyed iron powder is composed of 0.2-1.4% Mo, 0.05-0.25% Mn and less than 0.1% C, all percentage by weight of the pre-alloyed iron powder. The pre-alloyed iron powder is mixed with copper powder or copper oxide powder having a weight average particle size of at most 1/5 of the weight average particle size of pre-alloyed iron powder, the mixture is heated whereby the copper particles are diffusion bonded to the pre-alloyed iron powder. The copper content of the resulting diffusion bonded powder is 0.5-5%
by weight.
In the Dowa patent application, it is described a manufacturing method for producing a diffusion bonded copper containing iron powder wherein fin particulate copper oxide powder having a particle size of at most 51.1.m and a specific surface area of at least 10m2/g, is mixed with an iron containing powder. The mixture between the copper oxide powder and the iron containing
- 3 -powder is further subjected to a reducing atmosphere at a temperature between 700-950 C to reduce and deposit metallic copper on the iron powder surface at a content of 10-50% by weight of the resulting diffusion bonded powder.
The Sumitomo document discloses a diffusion alloyed iron powder having good compressibility suitable to be used for manufacturing compacted and sintered components having high strength, high toughness and excellent dimensional stability, without the need of using nickel as an alloying element.
The diffusion alloyed powder is produced by mixing atomized iron powder with iron oxide powder, at a content of 2-35% by weight of the iron powder, and copper powder and optionally molybdenum powder. The mixture is subjected to a reduction heat treatment process whereby the alloying elements and the reduced iron oxide is diffusion bonded to the surface of the atomized iron powder. The amount of copper in the resulting diffusion bonded powder is 0.5-
The Sumitomo document discloses a diffusion alloyed iron powder having good compressibility suitable to be used for manufacturing compacted and sintered components having high strength, high toughness and excellent dimensional stability, without the need of using nickel as an alloying element.
The diffusion alloyed powder is produced by mixing atomized iron powder with iron oxide powder, at a content of 2-35% by weight of the iron powder, and copper powder and optionally molybdenum powder. The mixture is subjected to a reduction heat treatment process whereby the alloying elements and the reduced iron oxide is diffusion bonded to the surface of the atomized iron powder. The amount of copper in the resulting diffusion bonded powder is 0.5-
4% by weight.
Although many attempts have been made in order to find a cost-effective diffusion- bonded copper containing iron powder for manufacturing pressed and sintered components, there is still a need for improving such powder with respect of cost and performance.
SUMMARY
The present invitation discloses a new diffusion- bonded powder consisting of an iron powder having 1-5%, preferably 1.5-4% and most preferably 1.5-3.5%
by weight of copper particles diffusion bonded the surfaces of the iron powder particles. The present invention also discloses a method for producing the diffusion-bonded powder as well as a method for manufacture of a component from the new diffusion-bonded powder and the produced component.
DETAILED DESCRIPTION
Iron powder The iron powder used to produce the diffusion bonded powder is an atomized iron powder, and in a preferred embodiment having an oxygen content of 0.3-1.2%, preferably 0.5-1.1% by weight, and a content of carbon of 0.1-0.5% by weight. In one embodiment the content of oxygen is 0.5-1.1% by weight and the content of carbon is above 0.3% by weight and up to 0.5% by weight. When water atomizing an iron melt it is more economical to allow higher contents of oxygen and carbon why this embodiment is preferred from a production economical point of view.
In an alternative embodiment the oxygen content is at most 0.15% by weight and the carbon content is at most 0.02% by weight.
By using an iron powder having a defined oxygen content, it has surprisingly been shown that the adhesion of the copper particles to the iron powder after the diffusion bonding-, reduction heat treatment-, process is significantly improved.
The maximum particle size of the iron powder is typically 250 m and at least 75% by weight is below 150 m. At most 30% by weight is below 45 m. The particle size measured according to IS04497 1983.
The total content of other unavoidable impurities, such as Mn, P, S, Ni and Cr is at most 1.5% by weight.
Copper containing powder The copper containing powder used to produce the diffusion bonded powder is cuprous oxide, (Cu2O) or cupric oxide (Cu0), preferably cuprous oxide is used.
The copper containing powder has a maximum particle size, X90, of 22 m, here
Although many attempts have been made in order to find a cost-effective diffusion- bonded copper containing iron powder for manufacturing pressed and sintered components, there is still a need for improving such powder with respect of cost and performance.
SUMMARY
The present invitation discloses a new diffusion- bonded powder consisting of an iron powder having 1-5%, preferably 1.5-4% and most preferably 1.5-3.5%
by weight of copper particles diffusion bonded the surfaces of the iron powder particles. The present invention also discloses a method for producing the diffusion-bonded powder as well as a method for manufacture of a component from the new diffusion-bonded powder and the produced component.
DETAILED DESCRIPTION
Iron powder The iron powder used to produce the diffusion bonded powder is an atomized iron powder, and in a preferred embodiment having an oxygen content of 0.3-1.2%, preferably 0.5-1.1% by weight, and a content of carbon of 0.1-0.5% by weight. In one embodiment the content of oxygen is 0.5-1.1% by weight and the content of carbon is above 0.3% by weight and up to 0.5% by weight. When water atomizing an iron melt it is more economical to allow higher contents of oxygen and carbon why this embodiment is preferred from a production economical point of view.
In an alternative embodiment the oxygen content is at most 0.15% by weight and the carbon content is at most 0.02% by weight.
By using an iron powder having a defined oxygen content, it has surprisingly been shown that the adhesion of the copper particles to the iron powder after the diffusion bonding-, reduction heat treatment-, process is significantly improved.
The maximum particle size of the iron powder is typically 250 m and at least 75% by weight is below 150 m. At most 30% by weight is below 45 m. The particle size measured according to IS04497 1983.
The total content of other unavoidable impurities, such as Mn, P, S, Ni and Cr is at most 1.5% by weight.
Copper containing powder The copper containing powder used to produce the diffusion bonded powder is cuprous oxide, (Cu2O) or cupric oxide (Cu0), preferably cuprous oxide is used.
The copper containing powder has a maximum particle size, X90, of 22 m, here
- 5 -defined as at least 90% of the particles are below the maximum particle size, and a weight average particle size, X50, of at most 15 m, preferably at most m, determined with laser diffractometry according to ISO 13320 : 2003.
Diffusion- bonded powder The iron powder is mixed with copper containing powder in proportions to obtain the final content of copper in the diffusion- bonded powder. After thoroughly mixing the powders, the mixture is subjected to a reduction-annealing process in a reducing atmosphere containing hydrogen at atmospheric pressure and at a time and temperature sufficient to reduce the copper containing powder into metallic copper and simultaneously allow copper to partially diffuse into the iron powder. Typically, the holding temperature is 800-980 C for a period of 20 minutes to 2 hours. The obtained material after the reduction-annealing process is in form of a loosely bonded cake which after a cooling step is subjected to crushing or gentle grinding followed by classifying yielding the final powder.
The maximum particle size of the obtained diffusion-bonded powder is 250 m and at least 75 by weight is below 150 m. At most 30% by weight is below 45 m.
The particle size measured according to IS04497 1983.
The oxygen content in the new powder is at most 0.16% by weight and the amount of other inevitable impurities is at most 1% by weight.
The apparent density of the new powder, AD, as measured according to ISO
3923:2008 is at least 2.70 g/cm3 in order to obtain sufficiently high green density and consequently sintered density at production of components.
The diffusion bonded powder is characterized by having a degree of bonding of copper to the iron ¨based powder with a SSF-factor of at most 2, as measured by the SSF method. It has also surprisingly been shown that when the oxygen content of the iron powder used for production of the new powder is between 0.3-1.2% by weight, the SSF- factor is at most 1.7.
The SSF method is here defined as a method for determine the degree of bonding of copper to the iron or iron-based powder by separating the diffusion bonded powder into two fractions, one fraction having a particle size below 45 m and another fraction having a particle size of 45 m and above. This separation may be performed with a 45 m standard sieve (325 mesh). The procedure according to ISO 4497:1986 may be followed with the proviso that only one sieve, 45 m, is used. The quotation between the copper content in
Diffusion- bonded powder The iron powder is mixed with copper containing powder in proportions to obtain the final content of copper in the diffusion- bonded powder. After thoroughly mixing the powders, the mixture is subjected to a reduction-annealing process in a reducing atmosphere containing hydrogen at atmospheric pressure and at a time and temperature sufficient to reduce the copper containing powder into metallic copper and simultaneously allow copper to partially diffuse into the iron powder. Typically, the holding temperature is 800-980 C for a period of 20 minutes to 2 hours. The obtained material after the reduction-annealing process is in form of a loosely bonded cake which after a cooling step is subjected to crushing or gentle grinding followed by classifying yielding the final powder.
The maximum particle size of the obtained diffusion-bonded powder is 250 m and at least 75 by weight is below 150 m. At most 30% by weight is below 45 m.
The particle size measured according to IS04497 1983.
The oxygen content in the new powder is at most 0.16% by weight and the amount of other inevitable impurities is at most 1% by weight.
The apparent density of the new powder, AD, as measured according to ISO
3923:2008 is at least 2.70 g/cm3 in order to obtain sufficiently high green density and consequently sintered density at production of components.
The diffusion bonded powder is characterized by having a degree of bonding of copper to the iron ¨based powder with a SSF-factor of at most 2, as measured by the SSF method. It has also surprisingly been shown that when the oxygen content of the iron powder used for production of the new powder is between 0.3-1.2% by weight, the SSF- factor is at most 1.7.
The SSF method is here defined as a method for determine the degree of bonding of copper to the iron or iron-based powder by separating the diffusion bonded powder into two fractions, one fraction having a particle size below 45 m and another fraction having a particle size of 45 m and above. This separation may be performed with a 45 m standard sieve (325 mesh). The procedure according to ISO 4497:1986 may be followed with the proviso that only one sieve, 45 m, is used. The quotation between the copper content in
- 6 -the finer fraction which passes the 45 p.m sieve, and the copper content in the coarser fraction which do not passes the 45 p.m sieve, gives a value, degree of bonding or SSF-factor.
SSF-factor=weight% Cu in the finer fraction, (-45 urn) / weight% Cu in the coarser fraction, (45 p.m and above).
The copper content in the fractions are determined by standard chemical methods with at least an accuracy of two figures.
Another distinguishing characterization of the new powder is that it enables production of sintered component characterized by having a minimum of variation of the nominal copper content, within each individual component as well as between the components. This can be expressed as that the maximum copper content in a cross section of a sintered component, produced at specified production conditions, should be at most 100% higher than the nominal copper content.
The samples for measuring variations in the copper content, maximum and minimum copper content, pore sizes and pore area are prepared according to the following;
A copper containing diffusion bonded powder according to the present invention is mixed with 0.5% of graphite, having a particle size, X90, of at most 15 m measured with laser diffraction according to ISO 13320:1999, and 0.9% of the lubricant described in the patent publication W02010-062250.. The obtained mixture is transferred into a compaction die for production of tensile strength samples (TS-bars) according to ISO 2740: 2009 and subjected to a compaction pressure of 600MPa. The compacted sample is thereafter ejected from the compaction die and subjected to a sintering process at 1120 C for a period of time of 30 minutes in an atmosphere of 90%nitrogen/10%hydrogen at atmospheric pressure.
The maximum copper content is measured in a cross section of the sintered component, i.e. a cross section perpendicular to the longest extension of the sintered TS-bar, through line scanning in a Scanning Electron Microscope (S EM) equipped with a system for Energy Dispersive Spectroscopy (EDS). The
SSF-factor=weight% Cu in the finer fraction, (-45 urn) / weight% Cu in the coarser fraction, (45 p.m and above).
The copper content in the fractions are determined by standard chemical methods with at least an accuracy of two figures.
Another distinguishing characterization of the new powder is that it enables production of sintered component characterized by having a minimum of variation of the nominal copper content, within each individual component as well as between the components. This can be expressed as that the maximum copper content in a cross section of a sintered component, produced at specified production conditions, should be at most 100% higher than the nominal copper content.
The samples for measuring variations in the copper content, maximum and minimum copper content, pore sizes and pore area are prepared according to the following;
A copper containing diffusion bonded powder according to the present invention is mixed with 0.5% of graphite, having a particle size, X90, of at most 15 m measured with laser diffraction according to ISO 13320:1999, and 0.9% of the lubricant described in the patent publication W02010-062250.. The obtained mixture is transferred into a compaction die for production of tensile strength samples (TS-bars) according to ISO 2740: 2009 and subjected to a compaction pressure of 600MPa. The compacted sample is thereafter ejected from the compaction die and subjected to a sintering process at 1120 C for a period of time of 30 minutes in an atmosphere of 90%nitrogen/10%hydrogen at atmospheric pressure.
The maximum copper content is measured in a cross section of the sintered component, i.e. a cross section perpendicular to the longest extension of the sintered TS-bar, through line scanning in a Scanning Electron Microscope (S EM) equipped with a system for Energy Dispersive Spectroscopy (EDS). The
- 7 -magnification is 130X, working distance is 10 mm and the scanning time is 1 minute.
The maximum copper content, measured by the above-mentioned method, is at any point along the line at most 100% higher than the nominal copper content.
It has also surprisingly been shown that when the oxygen content of the iron powder used for production of the new powder is between 0.3-1.2% by weight, the maximum copper content, measured by the above-mentioned method, is at any point along the line at most 80% higher than the nominal copper content and no measurements show 0% copper.
Alternatively, or in addition to the above-mentioned variation of copper content, a distinguishing characterization of the new powder is that it enables production of sintered component characterized by exhibiting a maximum size of the largest pore. This can be expressed as that the maximum pore area in a cross section of a sintered component, produced at the specified production conditions as described earlier, is at most 4000 m2.
The pore size analysis is carried out on a Light Optical Microscope (LOM) at a magnification of 100X with the aid of a digital video camera and a computer based software. The total measured area is 26.7 mm2. The software is operating in black and white mode and detects pores using "detection of black area in measured area", where black area is equal to pores.
The following definitions is applied:
Largest pore length: The largest length of all pores in the fields Largest pore area: The area of the largest pore from those measured in the fields.
Manufacture of sintered component Before compaction, the diffusion-bonded powder is mixed with various additives such as lubricants, graphite, and machinability enhancing additives.
Thus, an iron-based powder composition according to the invention contains or consists of 10 to 99.8 weight% of the diffusion bonded powder according to the invention, optionally graphite up to 1.5% weight% and when graphite is present the content is 0.3-1.5 weight%, preferably 0.15-1.2 weight%, 0.2 to 1.0 weight%
The maximum copper content, measured by the above-mentioned method, is at any point along the line at most 100% higher than the nominal copper content.
It has also surprisingly been shown that when the oxygen content of the iron powder used for production of the new powder is between 0.3-1.2% by weight, the maximum copper content, measured by the above-mentioned method, is at any point along the line at most 80% higher than the nominal copper content and no measurements show 0% copper.
Alternatively, or in addition to the above-mentioned variation of copper content, a distinguishing characterization of the new powder is that it enables production of sintered component characterized by exhibiting a maximum size of the largest pore. This can be expressed as that the maximum pore area in a cross section of a sintered component, produced at the specified production conditions as described earlier, is at most 4000 m2.
The pore size analysis is carried out on a Light Optical Microscope (LOM) at a magnification of 100X with the aid of a digital video camera and a computer based software. The total measured area is 26.7 mm2. The software is operating in black and white mode and detects pores using "detection of black area in measured area", where black area is equal to pores.
The following definitions is applied:
Largest pore length: The largest length of all pores in the fields Largest pore area: The area of the largest pore from those measured in the fields.
Manufacture of sintered component Before compaction, the diffusion-bonded powder is mixed with various additives such as lubricants, graphite, and machinability enhancing additives.
Thus, an iron-based powder composition according to the invention contains or consists of 10 to 99.8 weight% of the diffusion bonded powder according to the invention, optionally graphite up to 1.5% weight% and when graphite is present the content is 0.3-1.5 weight%, preferably 0.15-1.2 weight%, 0.2 to 1.0 weight%
- 8 -
9 PCT/EP2017/056123 of lubricant and up to 1.0 weight% of machinability enhancing additives, balanced with iron powder.
In one embodiment, an iron-based powder composition according to the invention contains or consists of 50 to 99.8 weight% of the diffusion bonded powder according to the invention, optionally graphite up to 1.5% weight% and when graphite is present the content is 0.3-1.5 weigh%, preferably 0.15-1.2 weight%, 0.2 to 1.0 weight% of lubricant, up to 1.0 weight% of machinability enhancing additives, balanced with iron powder.
After addition and admixing of additives the obtained mixture is subjected to a compaction process at a compaction pressure of at least 400 MPa, the subsequently ejected green component is sintered in a neutral or reducing atmosphere at a temperature of about 1050-1300 C for a period of time of 10 to 75 minutes. The sintering step may be followed by a hardening step, such as case hardening, through hardening, induction hardening, or a hardening process including gas or oil quenching.
FIGURE LEGENDS
Figure 1 shows variation in copper content for sample ac.
Figure 2 shows variation in copper content for sample bc.
Figure 3 shows variation in copper content for sample bd.
Figure 4 shows variation in copper content for sample be Figure 5 shows variation in copper content for sample ad.
EXAMPLES
Example 1 Various diffusion-bonded powders were produced by mixing iron powders according to table 1 with copper containing powders according to table 2 in an amount sufficient to yield a content of 3% of copper in the subsequently obtained diffusion-bonded powder. The obtained mixtures were subjected to a reduction-annealing process at a temperature of 900 C in a reducing atmosphere for a period of time 60 minutes. After the reduction-annealing process the obtained loosely sintered cake was gently crushed to a powder having a maximum particle size of 250 m.
The following tables show raw materials used.
Table 1 Iron powder 0 [%] C ro I D50 [rim]
a) 1.02 0.41 98 b) 0.08 0.004 107 Iron powder Table 2 Copper Cu [%] 0 [% ] D50 [PM] D95 [iim]
containing powder c) Cu2O 88.1 Not 15 22 measured d) Cu /00 99.5 0.18 85 160 e) Cu 200 99.6 0.15 60 100 Copper containing powder The obtained diffusion bonded powders were designated ac, bc, bd, be, ad and ae according to type of raw materials used.
Determination of SSF-factors for the diffusion bonded powders according to the invention were performed according to the method described in the detailed description. The following results according to table 3 were obtained.
Table 3 Sample SSF-factor ac 1.56 bc 1.97 SSF-factor
In one embodiment, an iron-based powder composition according to the invention contains or consists of 50 to 99.8 weight% of the diffusion bonded powder according to the invention, optionally graphite up to 1.5% weight% and when graphite is present the content is 0.3-1.5 weigh%, preferably 0.15-1.2 weight%, 0.2 to 1.0 weight% of lubricant, up to 1.0 weight% of machinability enhancing additives, balanced with iron powder.
After addition and admixing of additives the obtained mixture is subjected to a compaction process at a compaction pressure of at least 400 MPa, the subsequently ejected green component is sintered in a neutral or reducing atmosphere at a temperature of about 1050-1300 C for a period of time of 10 to 75 minutes. The sintering step may be followed by a hardening step, such as case hardening, through hardening, induction hardening, or a hardening process including gas or oil quenching.
FIGURE LEGENDS
Figure 1 shows variation in copper content for sample ac.
Figure 2 shows variation in copper content for sample bc.
Figure 3 shows variation in copper content for sample bd.
Figure 4 shows variation in copper content for sample be Figure 5 shows variation in copper content for sample ad.
EXAMPLES
Example 1 Various diffusion-bonded powders were produced by mixing iron powders according to table 1 with copper containing powders according to table 2 in an amount sufficient to yield a content of 3% of copper in the subsequently obtained diffusion-bonded powder. The obtained mixtures were subjected to a reduction-annealing process at a temperature of 900 C in a reducing atmosphere for a period of time 60 minutes. After the reduction-annealing process the obtained loosely sintered cake was gently crushed to a powder having a maximum particle size of 250 m.
The following tables show raw materials used.
Table 1 Iron powder 0 [%] C ro I D50 [rim]
a) 1.02 0.41 98 b) 0.08 0.004 107 Iron powder Table 2 Copper Cu [%] 0 [% ] D50 [PM] D95 [iim]
containing powder c) Cu2O 88.1 Not 15 22 measured d) Cu /00 99.5 0.18 85 160 e) Cu 200 99.6 0.15 60 100 Copper containing powder The obtained diffusion bonded powders were designated ac, bc, bd, be, ad and ae according to type of raw materials used.
Determination of SSF-factors for the diffusion bonded powders according to the invention were performed according to the method described in the detailed description. The following results according to table 3 were obtained.
Table 3 Sample SSF-factor ac 1.56 bc 1.97 SSF-factor
-10-Samples for measuring maximum pore size, maximum pore area and copper variation were prepared according to the procedure in the detailed description.
The maximum copper content was measured with the aid of a FEG-SEM, type Hitachi 5U6600. The EDS system was manufactured by Bruker AXS.
After inserting the specimen in the vacuum chamber and having adjusted the working distance to 10 mm, the electron ray was aligned to use the lowest possible magnification, 130X. The strait scanning line was chosen with as few pores as possible (deep pores could be capturing photons of importance). The scanning time was set to 1 min.
The results are presented in Figures 1-6 and in table 4.
The pore size analysis was carried out on a Light Optical Microscope (LOM) at a magnification of 100X with the aid of a digital video camera and a computer based software, Leica QWin. The module in the software called "Largest Pore Measurement" was used. The total measured area is 26.7mm2 corresponding to 24 measure fields.
All specimens were measured with a horizontal press orientation and a side way stepping of the cross section.
The software was operating in black and white mode and detected pores using "detection of black area in measured area", where black area is equal to pores.
The following table 4 shows the results from the measurements.
Diffusion Largest Largest Maximum % of Minimum bonded pore pore Cu nominal Cu powders length area content Cu content [lim] him21 [0/0] content [%]
ac Invention 144 3196 5.5 183 0.7 bc Invention 142 3130 5.9 197 0.0 bd Comparative 199 9034 8.1 270 0.0 be Comparative 160 5128 7.5 250 0.0 ad Comparative 178 8515 7.3 243 0.0 ae Comparative 162 5070
The maximum copper content was measured with the aid of a FEG-SEM, type Hitachi 5U6600. The EDS system was manufactured by Bruker AXS.
After inserting the specimen in the vacuum chamber and having adjusted the working distance to 10 mm, the electron ray was aligned to use the lowest possible magnification, 130X. The strait scanning line was chosen with as few pores as possible (deep pores could be capturing photons of importance). The scanning time was set to 1 min.
The results are presented in Figures 1-6 and in table 4.
The pore size analysis was carried out on a Light Optical Microscope (LOM) at a magnification of 100X with the aid of a digital video camera and a computer based software, Leica QWin. The module in the software called "Largest Pore Measurement" was used. The total measured area is 26.7mm2 corresponding to 24 measure fields.
All specimens were measured with a horizontal press orientation and a side way stepping of the cross section.
The software was operating in black and white mode and detected pores using "detection of black area in measured area", where black area is equal to pores.
The following table 4 shows the results from the measurements.
Diffusion Largest Largest Maximum % of Minimum bonded pore pore Cu nominal Cu powders length area content Cu content [lim] him21 [0/0] content [%]
ac Invention 144 3196 5.5 183 0.7 bc Invention 142 3130 5.9 197 0.0 bd Comparative 199 9034 8.1 270 0.0 be Comparative 160 5128 7.5 250 0.0 ad Comparative 178 8515 7.3 243 0.0 ae Comparative 162 5070
-11-From table 4 it can be concluded that components made from the diffusion bonded powders according to the invention show smaller largest pore areas and less variation in copper content compared to the comparative examples. It can further be concluded that when iron powder having higher oxygen content is used for producing the diffusion bonded powder according to the invention, the variation of copper content is less compared to when using iron powder having low oxygen content (ac-bc) Example 2 Four different iron-based powder compositions were prepared by mixing four different copper containing powders at an addition corresponding to 2 weight%
copper in the metal powder composition with the atomized iron powder ASC100.29, available from Hoganas AB, Sweden, 0.5% of synthetic graphite F10 from lmerys Graphite & Carbon, and 0.9% of the lubricant described in the patent publication W02010-062250.
The copper containing powders used were:
- The diffusion bonded powder ac according to Example 1.
- Distaloy0ACu, available from Hoganas AB Sweden. Distaoy0ACu is an iron powder having 10% of copper diffusion bonded on the surfaces if the iron powder.
- Cu- 200, the elementary Cu powder described in table 2.
- Cu- 100, the elementary Cu powder described in table 2.
The following table 5 shows the copper containing powders used and the content of the ingredients in the metal powder compositions.
copper in the metal powder composition with the atomized iron powder ASC100.29, available from Hoganas AB, Sweden, 0.5% of synthetic graphite F10 from lmerys Graphite & Carbon, and 0.9% of the lubricant described in the patent publication W02010-062250.
The copper containing powders used were:
- The diffusion bonded powder ac according to Example 1.
- Distaloy0ACu, available from Hoganas AB Sweden. Distaoy0ACu is an iron powder having 10% of copper diffusion bonded on the surfaces if the iron powder.
- Cu- 200, the elementary Cu powder described in table 2.
- Cu- 100, the elementary Cu powder described in table 2.
The following table 5 shows the copper containing powders used and the content of the ingredients in the metal powder compositions.
-12-Table 5 Iron-based Copper Copper ASC100.29 Graphite Lubricant powder containing containing [ /0] [94)] [%]
composition powder powder No. rd 1 ac 66.7 31.9 0.5 0.9 2 Distaloy0ACu 20 78.6 0.5 0.9 3 Cu-200 2 96.6 0.5 0.9 4 Cu-100 2 96.6 0.5 0.9 The iron-based powder compositions were compacted into test bars at 700 MPa according to IS03928. After compaction the ejected green test bars were sintered in an atmosphere of 90/10 N2/H2 at a temperature of 1120 C during 30 minutes and cooled to ambient temperature. Thereafter the test bars were subjected to through hardening at 860 C for 30 minutes at an atmosphere with a carbon potential of 0.5%, followed by quenching in oil.
The heat treated test bars were tested for fatigue strength at I:1=-1 with a run out limit of 2x106 cycles according to MPIF standard 56. The endurance limit was determined at 50% probability of survival.
The following table 6 shows he results from the fatigue test.
Table 6 Test bars made from Iron-based Fatigue strength 50% probability powder composition No. [MPa]
Table 6 shows that samples made from an iron-based powder mixture containing the diffusion alloyed powder according to the invention exhibits increased fatigue strength compared to samples made from iron-based powder mixtures containing elemental copper powders or known copper containing diffusion bonded powders.
composition powder powder No. rd 1 ac 66.7 31.9 0.5 0.9 2 Distaloy0ACu 20 78.6 0.5 0.9 3 Cu-200 2 96.6 0.5 0.9 4 Cu-100 2 96.6 0.5 0.9 The iron-based powder compositions were compacted into test bars at 700 MPa according to IS03928. After compaction the ejected green test bars were sintered in an atmosphere of 90/10 N2/H2 at a temperature of 1120 C during 30 minutes and cooled to ambient temperature. Thereafter the test bars were subjected to through hardening at 860 C for 30 minutes at an atmosphere with a carbon potential of 0.5%, followed by quenching in oil.
The heat treated test bars were tested for fatigue strength at I:1=-1 with a run out limit of 2x106 cycles according to MPIF standard 56. The endurance limit was determined at 50% probability of survival.
The following table 6 shows he results from the fatigue test.
Table 6 Test bars made from Iron-based Fatigue strength 50% probability powder composition No. [MPa]
Table 6 shows that samples made from an iron-based powder mixture containing the diffusion alloyed powder according to the invention exhibits increased fatigue strength compared to samples made from iron-based powder mixtures containing elemental copper powders or known copper containing diffusion bonded powders.
-13-
Claims (12)
1. An iron based powder consists of particles of reduced copper oxide diffusion bonded to the surface of an atomized iron powder wherein the content of copper is 1-5%, preferably 1.5-4% and most preferably 1.5-3.5% by weight of the iron based powder.
2. An iron based powder according to claim 1 wherein the maximum particle size is 250µm, at least 75% is below 150µm and at most 30% is below 45µm, the apparent density is at least 2.70g/cm3 and the oxygen content is at most 0.16% by weight and other inevitable impurities at most 1% by weight.
3. An iron based powder according to claim 2 having a SSF- factor of at most 2.0, preferably at most 1.7 wherein the SSF-factor is defined as the quotation between the Cu content in weight% in the fraction of the iron based powder which passes a 45 µm sieve and the Cu content in in weight% in the fraction of the iron based powder which do not passes a 45 µm sieve.
4. An iron based powder according to any of claims 1-3 characterized in that the maximum copper content in a cross section of a sintered component made from said iron based powder is at most 100% higher than the nominal copper content, preferably at most 80% higher than the nominal copper content wherein the sintered component is produced by mixing said iron-based powder with 0.5% of graphite, having a particle size, X90, of at most 15 m measured with laser diffraction according to ISO 13320:1999, and 0.9% of the lubricant described in the patent publication WO2010-062250 and the obtained mixture is transferred into a compaction die for production of tensile strength samples (TS-bars) according to ISO 2740: 2009 and subjected to a compaction pressure of 600MPa and the compacted sample is thereafter ejected from the compaction die and subjected to a sintering process at 1120°C for a period of time of 30 minutes in an atmosphere of 90%nitrogen/10%hydrogen at atmospheric pressure and the maximum copper content is determined through lines scanning in a Scanning Electron Microscope (SEM) equipped with a system for Energy Dispersive Spectroscopy (EDS) wherein the magnification is 130X, working distance is 10 mm and the scanning time is 1 minute.
5. An iron based powder according to any of claims 1-4 characterized in that the largest pore area in a cross section of a sintered component made from said iron based powder is at most 4 000µm2 wherein the sintered component is produced by mixing said iron-based powder with 0.5% of graphite, having a particle size, X90, of at most 15µm measured with laser diffraction according to ISO 13320:1999, and 0.9% of the lubricant described in the patent publication WO2010-062250 and the obtained mixture is transferred into a compaction die for production of tensile strength samples (TS-bars) according to ISO 2740: 2009 and subjected to a compaction pressure of 600MPa and the compacted sample is thereafter ejected from the compaction die and subjected to a sintering process at 1120°C for a period of time of 30 minutes in an atmosphere of 90%nitrogen/10%hydrogen at atmospheric pressure and the largest pore area is determined in a Light Optical Microscope (LOM) at a magnification of 100X with the aid of a digital video camera and a computer based software and the total measured area is 26.7mm2.
6. An iron-based powder composition containing or consisting of 10 to 99.8 weight% of the iron based powder according to any of claims 1-5, optionally graphite up to 1.5% weight% and when graphite is present the content is 0.3-1.5 weight%, preferably 0.15-1.2 weight%, 0.2 to 1.0 weight% of lubricant and up to 1.0 weight% of machinability enhancing additives, balanced with iron powder.
7. An iron-based powder composition containing or consisting of 50 to 99.8 weight% of the iron based powder according to any of claims 1-5, optionally graphite up to 1.5% weight% and when graphite is present the content is 0.3-1.5 weight%, preferably 0.15-1.2 weight%, 0.2 to 1.0 weight% of lubricant and up to 1.0 weight% of machinability enhancing additives, balanced with iron powder.
8. A process for producing an iron based powder comprising the following steps;
- providing an iron powder having a content of oxygen of 0.3-1.2% by weight, a content of carbon of 0.1-0.5% by weight, a maximum particle size of at most 250 µm and at most 30% by weight below 45µm and providing a copper containing powder having a maximum particle size, X90 of at most 22 µm and a weight average particle size, X50, of at most 15 µm, preferably at most 11µm, - mixing said iron powder and said copper containing powder, - subjecting said mixture to a reduction annealing process in a reducing atmosphere at 800-980°C for a period of 20 minutes to 2 hours, - and crushing the obtained cake and classifying into desired particle size.
- providing an iron powder having a content of oxygen of 0.3-1.2% by weight, a content of carbon of 0.1-0.5% by weight, a maximum particle size of at most 250 µm and at most 30% by weight below 45µm and providing a copper containing powder having a maximum particle size, X90 of at most 22 µm and a weight average particle size, X50, of at most 15 µm, preferably at most 11µm, - mixing said iron powder and said copper containing powder, - subjecting said mixture to a reduction annealing process in a reducing atmosphere at 800-980°C for a period of 20 minutes to 2 hours, - and crushing the obtained cake and classifying into desired particle size.
9. A process for making a sintered component comprising the steps of - providing an iron based powder composition according to any of claims 6-7, - subjecting the iron based powder composition to a compaction process at a compaction pressure of at least 400 MPa and ejecting the obtained green component, - sintering said green component in a neutral or reducing atmosphere at a temperature of about 1050-1300°C for a period of time of 10 to 75 minutes, - optionally hardening the sintered component in a hardening process such as case hardening, through hardening, induction hardening, or a hardening process including gas or oil quenching.
10. A sintered component made according to claim 9..
11. A sintered component according to claim 10 characterized in that the maximum copper content in a cross section is at most 100% higher than the nominal copper content, preferably at most 80% higher than the nominal copper content wherein the maximum copper content is determined through lines scanning in a Scanning Electron Microscope (SEM) equipped with a system for Energy Dispersive Spectroscopy (EDS) wherein the magnification is 130X, working distance is 10 mm and the scanning time is 1 minute.
12. A sintered component according to claim 10 or 11 characterized in that the largest pore area is at most 4 000µm2 wherein the largest pore area is determined in a Light Optical Microscope (LOM) at a magnification of 100X with the aid of a digital video camera and a computer based software and the total measured area is 26.7mm2.
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EP16161814.5 | 2016-03-23 | ||
PCT/EP2017/056123 WO2017162499A1 (en) | 2016-03-23 | 2017-03-15 | Iron based powder |
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ES2916093T3 (en) | 2016-03-23 | 2022-06-28 | Hoeganaes Ab Publ | iron-based powder |
CA3117043A1 (en) | 2018-10-26 | 2020-04-30 | Oerlikon Metco (Us) Inc. | Corrosion and wear resistant nickel based alloys |
CN114939657A (en) * | 2022-05-26 | 2022-08-26 | 上海竺泰新材料科技有限公司 | Method for manufacturing reduced iron powder with low apparent density |
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JP2022084836A (en) | 2022-06-07 |
US20210046543A1 (en) | 2021-02-18 |
ES2916093T3 (en) | 2022-06-28 |
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WO2017162499A1 (en) | 2017-09-28 |
BR112018069230B1 (en) | 2022-11-29 |
KR102376922B1 (en) | 2022-03-18 |
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JP7395635B2 (en) | 2023-12-11 |
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US11685979B2 (en) | 2023-06-27 |
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TW201736618A (en) | 2017-10-16 |
CA3017996C (en) | 2023-11-21 |
KR20180124918A (en) | 2018-11-21 |
EP3433392A1 (en) | 2019-01-30 |
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